Is there any way in which you can advertise for free on the internet?

Is there any way in which you can advertise for free on the internet? I wanted to kind of help some friends and make some advertising for their business, but of course WITHOUT breaking the law - is there any way to do so for free, or at least for a very cheap commission?

I've found that craigslist is the best place for me to advertise. Or you could also just google "free advertising online" :0)

Yes, Facebook is a good medium to advertise the business. We can reach a great amount of people quickly.Internet marketing involves E-mail marketing,SEO,article/blog submission,rewards or discounts through their website,online advertisements, Social marketing etc.There are providers like XnYnZ.com where they provide this email marketing service along with social marketing,SEO techniques to improve the business.